Dear Ms. Mulheir,
Thank you for posting your request on History Hub!
There are a variety of reasons a naturalization could be cancelled. In this case, the Certificate File (C-File) created by the Immigration and Naturalization Service (INS) should provide the details around the progression of events that led to the cancellation. The C-File may be requested through the US Citizenship and Immigration Services (USCIS) Genealogy Program.
We hope this is helpful. Best of luck with your family research!
[Information provided by Elizabeth Burnes, Subject Matter Expert]